Exclude build and test directories in export

Author: lukewaite

Diff for: .gitattributes

@@ -0,0 +1,11 @@
+# Path-based git attributes
+# https://www.kernel.org/pub/software/scm/git/docs/gitattributes.html
+
+# Ignore all test and documentation with "export-ignore".
+/.gitattributes     export-ignore
+/.gitignore         export-ignore
+/.scrutinizer.yml   export-ignore
+/.styleci.yml       export-ignore
+/.travis.yml        export-ignore
+/phpunit.xml.dist   export-ignore
+/tests              export-ignore